本論文呈現了兩個應用於無線感測網路之超低功耗喚醒接收機設計，兩顆晶片皆操作於工業、科學與醫學頻帶(ISM band)，並可分別接收並解調振幅鍵控調變(ASK)以及頻率鍵控調變(FSK)之訊號。
第一個喚醒接收機可解調振幅鍵控調變訊號，基於直接偵測架構，提出了互補式全差動電流再利用之包絡偵測器，整合了輸入匹配網路做為射頻接收機前端，在提高靈敏度的同時，去除高耗能的低雜訊放大器(LNA)以及本地振盪器(LO)之需求，大幅地降低所需功耗。本設計使用台積電提供的0.18微米CMOS製程，可操作於2.4千兆赫茲，在提供0.8伏特電壓源時，僅消耗4.5微瓦，並在每秒400千位元的資料傳輸率下，達到-65 dBm的靈敏度。與國際重要期刊以及會議論文比較下，本設計達到每位元資料傳輸僅消耗11.25微微焦耳，為最佳之能源使用效率。
為了讓接收端與發射端地功耗預算能夠平衡，使用FSK調變需要較複雜的接收機架構，然而卻可減輕發射端的負擔，因此第二個喚醒接收機被設計來解調FSK訊號，關鍵技術在於提出使用注入鎖定技術的鑑頻器做為射頻前端，將FSK訊號轉換成ASK訊號，接著再經由直接偵測架構，完成最簡單的FSK接收機架構。設計上的最主要限制在於振盪器的功耗，為了實現超低功耗，將製作在印刷電路板上的環形天線同時做為振盪器的電感，可實現高品質因數(Q≈150)，並整合天線的設計，大幅降低所需功耗並提升靈敏度。FSK喚醒接收機同樣使用台積電提供的0.18微米CMOS製程，提供1伏特電壓，消耗7.4微瓦，可在433百萬赫茲的頻率，每秒200千位元的資料傳輸率下，達到-70 dBm的靈敏度，並且每位元消耗37微微焦耳，與文獻相比，為最低功率消耗以及最佳能源效率。

This thesis presented two ultra-low-power wake-up receivers (WuRx) for wireless sensor network applications. They featured narrow band operation at the widely used industrial scientific medical (ISM) band, and were capable of receiving and demodulating the on-off keying (OOK) and frequency-shift keying (FSK) modulated wake-up signal, respectively.
The first OOK WuRx was based on direct-detection topology, using the proposed fully-differential complementary current-reuse RF detector embedded with input matching network, obviating the need of power-thirsty RF low noise amplifier (LNA) and local oscillator (LO). It was fabricated in 0.18-µm CMOS technology, featured -65 dBm sensitivity with 400 kbps data rate at 2.4 GHz while consuming only 4.5 µW from a 0.8 V supply voltage. As a result, this work achieves the best energy efficiency of 11.25 pJ/bit compared to the state-of-the-art OOK WuRxs.
The second work, a FSK WuRx was presented to balance the power budget between Rx and Tx. The architecture was based on an injection-locked oscillator (ILO) as a FSK to ASK conversion circuit. The ASK signal was followed by the direct detection topology to demodulate the wake-up signal. The significant design limitation was the power constraint of the ILO. This work utilized an external high-Q inductor (Q≈150), fabricated on printed circuit board (PCB) as a loop antenna for receiving RF signal. The chip was fabricated in 0.18-µm CMOS technology, featured -70 dBm sensitivity and 200 kbps data rate at 433 MHz while consuming 7.4 µW from a 1 V supply voltage. It reached the energy efficiency of 37 pJ/bit.

[1]. J. Rabaey, J. Ammer, T. Karalar, S. Li, B. Otis, M. Sheets, and T. Tuan, PicoRadios for wireless sensor networks: the next challenge in ultra-low power design," in IEEE ISSCC Digest of Technical Papers, Feb. 2001, pp. 200-201.
[2]. E.-Y. Lin, J. Rabaey, and A.Wolisz, Power-effcient rendezvous schemes for dense wireless sensor networks," IEEE International Conference on Communications, vol. 7, pp. 3769-3776, June 2004.
[3]. I. Demirkol, C. Ersoy, and E. Onur, “Wake-up receivers for wireless sensor networks: benefits and challenges,” IEEE Wireless Communications, vol. 16, no. 4, pp. 88-96, 2009.
[4]. M. Raju and M. Grazier, "Ultra Low Power Meets Energy Harvesting: A game-changing combination for design engineers," Texas Instruments, 2010.
[5]. J. Bae, L. Yan, and H.-J. Yoo, “A low energy injection-locked FSK transceiver with frequency-to-amplitude conversion for body sensor applications,” Solid-State Circuits, IEEE Journal of, vol. 46, no. 4, pp. 928 –937, april 2011.
[6]. J. Bohorquez, A. Chandrakasan, and J. Dawson, “A 350-µW CMOS MSK transmitter and 400 W OOK super-regenerative receiver for medical implant communications,” IEEE J. Solid-State Circuits, vol. 44, no. 4, pp. 1248–1259, Apr. 2009.
[7]. J. Choi, K. Lee, S.-O. Yun, S.-G. Lee, and J. Ko, " An interference-aware 5.8GHz wake-up radio for ETCS," in IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 2012, pp. 446-447.
[8]. B. Otis, Y. H. Chee, and J. Rabaey, “A 400-µW-RX, 1.6-mW-TX super-regenerative transceiver for wireless sensor networks,” in IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 2005, pp. 396-397.
[9]. N. Pletcher, S. Gambini, and J. Rabaey, "A 65-µW, 1.9 GHz RF to digital baseband wakeup receiver for wireless sensor nodes," in IEEE Custom Integrated Circuits Conference, 2007, pp. 539-542.
[10]. X. Huang, S. Rampu, X. Wang, G. Dolmans, and H. de Groot, "A 2.4GHz/915MHz 51-µW wake-up receiver with offset and noise suppression," in IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 2010, pp. 222-223.
[11]. N. M. Pletcher, S. Gambini, and J. M. Rabaey, "A 2GHz 52-µW Wake-Up Receiver with -72dBm Sensitivity Using Uncertain-IF Architecture," in IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 2008, pp. 524-525.
[12]. S. Drago, D. M. W. Leenaerts, F. Sebastiano, L. J. Breems, K. A. A. Makinwa, and B. Nauta, "A 2.4GHz 830pJ/bit duty-cycled wake-up receiver with -82dBm sensitivity for crystal-less wireless sensor nodes," in IEEE Int. Solid-State Circuits Conf. Dig. Tech. Papers, 2010, pp. 224-225.
[13]. K.-W. Cheng, X. Liu, and M. Je, “A 2.4/5.8 GHz 10-µW Wake-Up Receiver With -65/-50 dBm Sensitivity Using Direct Active RF Detection,” in IEEE Asian Solid-State Circuits Conf. Dig. Tech. Papers, 2012, pp. 337-340.
[14]. N. E. Roberts and D. D. Wentzloff, “A 98nW wake-up radio for wireless body area networks,” in IEEE Radio Freq. Integrated Circuits Symp. Dig., 2012, pp. 373-376.
[15]. C. Hambeck, S. Mahlknecht, and T. Herndl, “A 2.4-µW Wake-up Receiver for wireless sensor nodes with -71dBm sensitivity,” in Proc. IEEE Int. Symp. on Circuits and Systems, 2011, pp. 534-537.
[16]. T. Wada, M. Ikebe, and E. Sano, “60-GHz, 9-µW wake-up receiver for short-range wireless communications,” in Proc. IEEE European Solid-State Circuits Conf., 2013, pp. 383-386.
[17]. H. Milosiu, F. Oehler, M. Eppel et al., “A 3-µW 868-MHz wake-up receiver with -83 dBm sensitivity and scalable data rate,” in Proc. IEEE European Solid-State Circuits Conf., 2013, pp. 387-390.
[18]. P.J. Langlois, A. Demosthenous, “Possible Benefitsof Moderate Inversion for MOSFET Transconductors,” in Proc. 2006 IEEE Int. Symp. Circuits Syst. (ISCAS’06), Island of Kos, Greece, May 2006, pp. 449–452.
[19]. E. Nilsson, C. Svensson, “Envelope Detector Sensitivity and Blocking Characteristics,” in Proc. 20th Eur. Conf. Circuit Theory Design (ECCTD), Aug. 2011, pp. 773–776.
[20]. N. M. Pletcher, S. Gambini, and J. M. Rabaey, "A 52-µW Wake-Up Receiver with -72dBm Sensitivity Using Uncertain-IF Architecture," in IEEE Journal of Solid-State Circuits, Volume: 44 Issue: 1 , Jan 2009 Page(s): 269 - 280
[21]. Porret, A.-S.; Melly, T.; Python, D.; Enz, C.C.; Vittoz, E.A.; “An ultralow-power UHF transceiver integrated in a standard digital CMOS process: architecture and receiver” Solid-State Circuits, IEEE Journal of , Volume: 36 Issue: 3 , March 2001 Page(s): 452 -466
[22]. H.-Y. Shih, et al., “An ultralow power multirate FSK demodulator with digital-assisted calibrated delay-line based phase shifter for high-speed biomedical zero-IF receivers” Very Large Scale Integration (VLSI) Systems, IEEE Transactions on, vol. PP, no. 99, pp. 1, Jan 2014
[23]. T.Roh, et al., “A 10Mb/s 4ns Jitter Direct Conversion Low Modulation Index FSK Demodulator for Low-energy Body Sensor Network,” IEEE ISCAS, June 2010
[24]. M. Lont, D. Milosevic, G. Dolmans, and van Roermund, “ Mixer-First FSK Receiver With Automatic FrequencyControl for Body Area Networks ,” Circuits and Systems I: Regular Papers, IEEE Transactions on, 2013 , Page(s): 2051 – 2063.
[25]. J. Bae, N. Cho, and H.-J. Yoo, “A 490 Wfully MICS compatible FSK transceiver for implantable devices,” in Symp. VLSI Circuits Dig. Tech Papers, 2009, pp. 36–37.
[26]. J. Pandey, J. Shi, and B. Otis, “A 120µW MICS/ISM-Band FSK Receiver with a 44µW Low-Power Mode Based on Injection-Locking and 9x Frequency Multiplication,” in ISSCC, 2011, vol. 61, no. 10, pp. 460-462.
[27]. J. Ayers et al., “An ultralow-power receiver for wireless sensor networks,” IEEE J. Solid-State Circuits, vol. 45, no. 9, pp. 1759–1769, Sep. 2010.
[28]. H. Yan, J. G. Macias-Montero, A. Akhnoukh, L. C. N. de Vreede, J. R. Long, and J. N. Burghartz, “An ultra-low-power BPSK receiver and demodulator based on injection-locked oscillators,” IEEE Trans. Microw. Theory Tech., vol. 59, no. 5, pp. 1339–1349, May 2011.
[29]. J. Bae, and H.-J. Yoo, “A 45-μW injection-locked FSK wake-up receiver for crystal-less wireless body-area-network” Solid State Circuits Conference, 2012 IEEE Asian , pp. 333 –336, 12-14 Nov. 2012.
[30]. H. Cho, J. Bae, and H. J. Yoo, “A 37.5-μW Body Channel Communication Wake-Up Receiver With Injection-Locking Ring Oscillator for Wireless Body Area Network,” Circuits and System I: Regular Papers, IEEE Transactions on, vol. 60, no. 5, pp. 1200-1208, May 2013.
[31]. B. Razavi, “A study of injection locking and pulling in oscillators,” Solid-State Circuits, IEEE Journal of , Volume: 39 Issue: 9 , Sept 2004 Page(s): 1415 – 1424.
[32]. S. Shekhar, G. Balamurugan, D.J. Allstot, M, Mansuri, “Strong Injection Locking in Low- Q LC Oscillators: Modeling and Application in a Forwarded-Clock I/O Receiver,” Circuits and System I: Regular Papers, IEEE Transactions on, vol. 56, no. 8, pp. 1818-1829, Aug 2009.
[33]. A.D. Berny, A.M. Niknejad, R.G. Meyer, “A 1.8-GHz LC VCO with 1.3-GHz tuning range and digital amplitude calibration,” Solid-State Circuits, IEEE Journal of , Volume: 40 Issue: 4 , April 2005 Page(s): 909 – 917.
[34]. B. Calvo, A.J. Lopez-Martin, S. Balasubramanian, and J. Ramirez-Angulo, “Linear-enhanced V to I converters based on MOS resistive source degeneration,” Circuits and Systems, 2008. ISCAS 2008. IEEE International Symposium on, 18-21 May 2008 Page(s): 3118 – 3121.